title: Reporting and incidence trends of hydatidiform mole in Sweden 1973-2004.
abstract: OBJECTIVE
  To examine temporal trends in the incidence of hydatidiform mole (HM) in relation to maternal age, the occurrence of choriocarcinoma in women with a history of HM and the extent of underreporting of HM to the Swedish Cancer Register (SCR).
  
  
  METHODS
  Women registered with a diagnosis of HM were identified in the Swedish Cancer Register and the Swedish Inpatient Register (IPR). Record linkage to the Medical Birth Register provided information to assess the incidence of HM.
  
  
  RESULTS
  We identified 3 844 unique cases of HM in the SCR and in the IPR combined between 1973 and 2004, yielding an incidence of 1.2 per 1 000 deliveries. The incidence of HM increased during the period under study. The highest incidence was observed in women below 20 and above 39 years of age. Of all registered cases of choriocarcinoma, 37% occurred in women with a previous history of HM. The risk of choriocarcinoma following HM was 1.3%, compared to 0.005% in women without a previous molar diagnosis. The records of the Cancer Register included 83.2% of all identified cases of HM.
  
  
  CONCLUSIONS
  The incidence of HM in Sweden has increased over time, and is characterized by a bimodal pattern with distinctive peaks in the youngest and oldest women of reproductive age. More than one third of all women registered with choriocarcinoma had a previous diagnosis of HM. Despite mandatory reporting, there was evidence of underreporting of HM to the SCR that remained virtually unchanged over calendar time.
authors.affiliation: Department of Obstetrics and Gynecology, Södersjukhuset, Stockholm, Sweden. sahar.salehi@sodersjukhuset.se
authors.forename: Sahar
authors.initials: S
authors.lastname: Salehi
authors.forename: Sandra
authors.initials: S
authors.lastname: Eloranta
authors.forename: Anna L V
authors.initials: AL
authors.lastname: Johansson
authors.forename: Mats
authors.initials: M
authors.lastname: Bergström
authors.forename: Mats
authors.initials: M
authors.lastname: Lambe
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006828:Hydatidiform Mole / Q000453:epidemiology*; D015994:Incidence; D011247:Pregnancy; D012042:Registries / Q000592:standards / Q000706:statistics & numerical data*; D012107:Research Design / Q000592:standards; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D014594:Uterine Neoplasms / Q000453:epidemiology*